JPH07199098A - Light beam scanning device - Google Patents

Abstract

PURPOSE:To provide a high quality image without the irregularity of a joint even through a scanning shake in the scanning direction is caused due to the rotation unevenness or the like of a light deflector. CONSTITUTION:A scanning position obtained by the light deflectors 14a and 14b is decided so as to make two partial scanning areas SA1 and SA2 splitting an area to be scanned on photosensitive material 3 mutually partially overlapped. Also laser beams LB1 and LB2 emitted from first and second laser light sources 10a and 10b are modulated and adjusted by optical modulating devices 11a and 11b so that the total of the intensity of both laser beams LB1 and LB2 is nearly the same size as a part excluding an overlapped scanning area SA0 by increasing or decreasing the intensity of the first laser beam LB1 and the second laser beam LB2 at the overlapped area SA0 in reverse proportion to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light beam scanning device for scanning a surface to be scanned with a light beam.

[0002]

2. Description of the Related Art Conventionally, as a light beam scanning device, there is known a light beam scanning device in which a light beam from a light source is reflected by an optical deflector such as a polygon mirror and then the light beam is incident on a surface to be scanned through a scanning lens. ing. In such a light beam scanning device, when the surface to be scanned is enlarged, the scanning lens has to have a large focal length, which makes it difficult to make the surface to be scanned wide. Therefore, a technique has been proposed in which the surface to be scanned is divided into a plurality of parts, and the divided partial scanning regions are individually scanned, thereby making it possible to correspond to a wide surface of the surface to be scanned (Japanese Patent Publication No. 5-57566). "Wide-area optical scanning device" described.

[0003]

However, in the above-mentioned conventional technique, the following problems occur at the connecting portion between the partial scanning areas. At the connecting portion, the end of the scanning line on one side and the starting end of the scanning line on the other side must be perfectly aligned, but uneven rotation occurs in the optical deflector or feeding in the sub-scanning direction occurs. When the camera shakes in the main scanning direction, the terminal end and the starting end may be separated from each other or overlap each other. As a result, a so-called seam shift such as overlapping or dropping of images occurred due to missing or overlapping scanning lines. In particular, when a line drawing is drawn as an image, the line is thickened or chipped at the joint portion, resulting in a fatal deterioration in image quality.

The present invention has been made in view of these problems, and it is possible to obtain an image with no seam deviation even if there is scanning blur in the scanning direction due to uneven rotation of the optical deflector. An object is to provide a light beam scanning device.

[0005]

In order to achieve such an object, the following constitution is adopted as a means for solving the above problems.

The light beam scanning device of the present invention uses a scanning means provided with a light beam emitting unit for emitting a light beam and an optical deflector for deflecting the light beam, and makes the surface to be scanned into a plurality of lines in the scanning direction. In a light beam scanning device that individually scans divided partial scanning regions, the deflection direction of the optical deflector is determined such that two adjacent ones of the plurality of partial scanning regions partially overlap in the scanning direction. , When scanning one of the two partial scan areas, the energy of the light beam monotonically decreases in the overlapping portion of the partial scan areas, and when scanning the other partial scan area of the two The energy of the light beam monotonically increases in the overlapping portion of the partial scanning area,
And, the light beam adjusting means for adjusting the light beam from the light beam emitting portion is provided so that the total energy of the light beams in the overlapping portion of both is substantially the same as the portion other than the overlapping portion. The summary is.

[0007]

In the light beam scanning device configured as described above, scanning is performed such that two adjacent ones of the plurality of partial scanning regions partially overlap in the scanning direction. Further, when scanning one of the two partial scanning regions, the energy of the light beam monotonically decreases at the overlapping portion of the partial scanning regions, and the other partial scanning region of the two is scanned. At this time, the energy of the light beam is monotonically increased at the overlapping portion of the partial scanning areas, and the light beam energy at the overlapping portion is substantially equal to that of the portion other than the overlapping portion. The light beam from the beam emitting unit is adjusted by the light beam adjusting means.

As a result, even when the partial scanning area to be scanned by the optical deflector causes rotational unevenness and is displaced in the scanning direction, as long as the displacement amount is suppressed within the overlapping portion between the partial scanning areas. The energy of the light beam can be made to have substantially the same constant size as the portion other than the overlapping portion. In this way, it works to prevent chipping or duplication on the scan lines.

[0009]

Preferred embodiments of the present invention will be described below in order to further clarify the structure and operation of the present invention described above.

FIG. 1 is a perspective view showing a main part of a graphic pattern drawing device 1 as a light beam scanning device of the first embodiment. The figure pattern drawing apparatus 1 is a so-called plane scanning type image recording apparatus, and as shown in FIG. 1, a table 5 having a cubic shape and holding a photosensitive material 3 as a recording medium on the upper surface thereof.
And a mounting table 7 arranged above the table 5, and an optical system 8 mounted on the mounting table 7. As the photosensitive material 3, a printed circuit board blank coated with a visible light resist, a PS plate (aluminum-based printing plate material), or the like is used.

The optical system 8 includes two laser light sources 10a and 1a.
0b emits the first and second laser beams LB
1, LB2 are respectively guided to the photosensitive material 3, and an optical modulator 11 provided in the traveling path of the first laser beam LB1.
a, a reflection mirror 12a, a beam expander 13a, a light deflector 14a, a scanning lens 15a, and a light modulator 11b, a reflection mirror 12b, a beam expander 13b, and a light deflection device provided in the traveling path of the second laser beam LB2. Device 14b and scanning lens 15b, and both scanning lenses 15
and a folding mirror 16 for folding back the laser beams LB1 and LB2 which have passed through a and 15b to the photosensitive material side. An argon laser is used as the laser light sources 10a and 10b.

The first laser beam LB1 emitted from the first laser light source 10a enters the light modulator 11a and is modulated according to the image signal to be recorded on the photosensitive material 3 held on the table 5. Is done. The laser beam LB1 emitted from the optical modulator 11a is then sent to the beam expander 13a, converted into a beam having a relatively large diameter, and incident on the optical deflector 14a.

The optical deflector 14a uses a polygon mirror (rotary polygon mirror), and drives the main scanning motor 17a (FIG. 3) to rotate the polygon mirror about its central axis A0. In such an optical deflector 14a, the laser beam LB1 incident through the beam expander 13a is reflected by the reflecting surface of the polygon mirror, and the traveling direction of the reflected laser beam LB1 is crossed with the central axis A0 in the scanning plane. To deflect.

The laser beam LB1 emitted from the optical deflector 14a passes through the scanning lens 15a which adjusts the focal length by giving the optical system a special distortion aberration, and the folding mirror 1
6 and is reflected by the folding mirror 16. The laser beam LB1 reflected by the folding mirror 16 is − in the figure.
It advances in the z direction and is sent to the photosensitive material 3 held on the surface of the table 5. Then, by rotating the optical deflector 14a at a constant speed by the main scanning motor, the surface of the photosensitive material 3 is moved in the main scanning direction (the y direction in the drawing) by the laser beam LB1.
To be scanned.

The second laser beam LB2 emitted from the second laser light source 10b has the same path as that of the first laser beam LB1, and the optical modulator 11b and the reflection mirror 1 are provided.
2b, the beam expander 13b, the optical deflector 14b, the scanning lens 15b, and the folding mirror 16, and the sheet is sent to the photosensitive material 3 held on the surface of the table 5 by the folding mirror 16. Then, by rotating the optical deflector 14a at a constant speed by the main scanning motor, the second laser beam LB2
The surface of the photosensitive material 3 is scanned in the main scanning direction (y direction in the drawing).

On the other hand, the table 5 holding the photosensitive material 3
Is driven by the sub-scanning motor 21 in the −x direction, that is,
The photosensitive material 3 moves in a direction orthogonal to the main scanning direction y.
As a result, the surface of the photosensitive material 3 is scanned in the sub-scanning direction (x direction in the drawing) by the first and second laser beams LB1 and LB2 reflected by the folding mirror 16.

These first and second laser beams L
As shown in FIG.
Two two-dimensional scanning areas are formed as shown in FIG. That is, as shown in FIG. 2, the photosensitive material 3 is scanned with the first laser beam LB1 in a first partial scan area SA1.
And a second partial scan area SA2 is formed by scanning with the second laser beam LB2. Both partial scan areas SA
1 and SA2 have the same size, and are larger in the main scanning direction than the size of the entire scanning region bisected in the main scanning direction (scanning direction), and both partial scanning regions SA1 and SA2 are partially in the main scanning direction. An overlapping scan area (hatched area in the figure) SA0 is provided.

Next, the configuration of the electric control system of the graphic pattern drawing apparatus 1 will be described with reference to FIG. As shown in FIG. 3, this control system includes a front end processor 31.
And a modulation controller 33 for controlling the optical modulators 11a and 11b.
And the main scanning motors 17a and 17b and the sub-scanning motor 2
1 and a scanning control unit 35 for controlling the number 1.

The front-end processor 31 inputs pre-generated whole image data including various figures and divides the whole image data into two partial image data. An example of this division is shown in FIG. As shown in FIG. 4, the entire image data DP includes first partial image data D1 indicating the right half of the entire image region indicated by the entire image data DP and second partial image data D2 indicating the left half of the entire image region. Is divided into and The first partial image data D
1 and the second partial image data D2 correspond to the first partial scanning area SA by the scanning of the first laser beam LB1 described above.
1 and the second partial scanning area SA2 by the scanning of the second laser beam LB2, the areas are determined, and in actuality, the entire image area is divided into two equal parts in the horizontal direction. Take a slightly larger area.

Such a front end processor 31
Stores the first partial image data D1 in the first buffer 40a and the second partial image data D2 in the second buffer 40b, as shown in FIG. The modulation control unit 33 controls the first and second partial image data D
1, D2 based on the first and second optical modulators 11a,
11b is controlled respectively and includes the following parts. That is, the modulation control unit 33 includes the modulation controller 41.
R, which is related to the first partial image data D1
IP (raster image processor) 42a, image memory 43a, adder 44a, D / A converter 45a, modulator driver 46a, address counter 47a, correction data memory 48a, and second partial image data D2 RIP 42b, image memory 43b, adder 44
b, a D / A converter 45b, a modulator driver 46b, an address counter 47b, and a correction data memory 48b.

The partial image data D1 stored in the first buffer 40a is converted to bitmap raster data by the RIP 42a and stored in the image memory 43a. On the other hand, the front-end processor 31 sends a control signal S1 to the modulation controller 41 to operate the modulation controller 41. The modulation controller 41 is
A sub-scanning position signal S2 indicating a position in the sub-scanning direction is received from a scanning controller provided in the scan control unit 35, and a reference signal S3 based on the sub-scanning position signal S2 is received.
To the address counter 47a. Address counter 4
7a receives the reference signal S3, calculates the address value, and sends the address signal S4 indicating the address value to the image memory 43a. The image memory 43a sequentially reads the raster data for each pixel based on the address signal S4 and the reference signal S3, and sends the raster data to the adder 44a.

The address counter 47a also transfers the address signal S4 to the correction data memory 48a. The correction data memory 48a is the front end processor 31.
The correction data transferred from is stored in advance, and the content of the correction data is read based on the address signal from the address counter 47a and transferred to the adder 44a.
The correction data is for weighting the raster data stored in the image memory 43a, and is composed of weighting values for one line of the raster data.

The contents of the correction data are shown in FIG. As shown in FIG. 5, in an area where the address value is smaller than the predetermined value N0, the weighting value increases quadratically from the value 0 to the value 1 as the address value increases, and the address value becomes the predetermined value N1 or more. Then, the weighting value holds the value 1. The predetermined value N1 is the size of the overlapping scanning area SA0 which is an overlapping portion of the partial scanning area SA1 that can be scanned by the first laser beam LB1 and the partial scanning area SA2 that can be scanned by the second laser beam LB2. It corresponds to.

The adder 44a receives the raster data from the image memory 43a and the correction data from the correction data memory 48a, and corrects the raster data by superimposing the correction data on the raster data. Next, the corrected raster data is transferred from the adder 44a to the D / A converter 4
5a, converted into an analog signal by the D / A converter 45a, and transferred to the modulator driver 46a. The modulator driver 46a drives and controls the first optical modulator 11a according to the analog signal.

On the other hand, each part from the RIP 42b related to the second partial image data D2 including the modulation controller 41 to the correction data memory 48b operates in the same manner as the side related to the first partial image data D1 described above. Then, while correcting the raster data stored in the image memory 43b with the contents of the correction data memory 48b, the optical modulator 11b is drive-controlled based on the corrected raster data.

The contents of the correction data stored in the second correction data memory 48b are different from those in the first correction data memory 48a. FIG. 6 shows the contents of the second correction data. As shown in FIG. 6, in the area where the address value N is equal to or less than the predetermined value N2, the value 1 is set as the weighting value.
And the address value N becomes larger than the predetermined value N2, the weighting value decreases in a quadratic curve from the value 1 to the value 0 as the address value increases. In addition, 2 showing this decrease
The quadratic curve and the quadratic curve showing the increase in the range in which the number of bits N is smaller than N1 in the correction data stored in the first correction data memory 48a described above have weighting values of 0.
It is symmetrical with respect to a straight line that is 5.

By the drive control of the optical modulators 11a and 11b by the modulation control unit 33 thus constructed, the optical modulator 1
The intensity (energy) of the laser beam emitted from 1a and 11b changes as shown in FIG. As can be seen from FIG. 7, in the overlapping scanning area SA0 of the partial scanning area SA1 by the first laser beam LB1 and the partial scanning area SA2 by the second laser beam LB2, the intensity of the first laser beam LB1 is 0. To a predetermined value P0, the intensity of the second laser beam LB2 is increased to a predetermined value P0.
To a value of 0 decrease quadratically. The sum of the intensities of the two laser beams LB1 and LB2 is
1 and LB2 have the same size as the strength of the scanning area other than the overlapping scanning area SA0.

Returning to FIG. 3, the scanning controller 35 includes a scanning controller 51 for controlling the operations of the main scanning motors 17a and 17b and the sub scanning motor 21. The scanning controller 51 drives the main scanning motors 17a and 17b by controlling the main scanning drivers 53 and 54, and
The sub scanning motor 21 is driven by controlling the sub scanning driver 55. As a result, the first light deflector 14a and the second light deflector 14b rotate at a constant speed, and in parallel therewith, the table 5 holding the photosensitive material 3 moves at a constant speed in the -x direction in FIG. . Further, the scanning controller 51 is
The sub-scanning position signal S2 is also sent to the modulation controller 41.

As described above in detail, in the graphic pattern drawing apparatus 1 of the first embodiment, the two partial scan areas SA1 and SA2 which divide the scan area on the photosensitive material 3 are partially overlapped with each other. , The scanning positions by the optical deflectors 14a and 14b are determined, and further, in the overlapping area SA0, the intensity of the first laser beam LB1 and the second laser beam LB2 increase or decrease in inverse proportion to each other, The sum of the intensities of the two laser beams LB1 and LB2 is the overlap scanning area S
The laser beams LB1 and LB2 emitted from the first and second laser light sources 10a and 10b are made to have substantially the same size as the portions other than A0, and the optical modulators 11a and 11b.
The modulation is adjusted by.

For this reason, the optical deflector 14a causes uneven rotation, and as shown in FIG. 8, one laser beam LB1.
Even when the partial scanning area SA1 due to is shifted from the correct position shown by the broken line to the position shown by the solid line, the total sum of the intensities of the first laser beam LB1 and the second laser beam LB2 is different from the overlapped region. It can be of almost the same size as the part. Therefore, both laser beams LB1, LB
It is possible to prevent missing or overlapping of the scanning lines in the connecting portion between the scanning area SA1 and the scanning area SA2 due to 2. As a result, it is possible to realize a wide surface to be scanned and, at the same time, to overlap or drop an image, that is, a so-called seam. A high-quality graphic pattern with no deviation can be drawn on the photosensitive material 3.

In the first embodiment, since the intensity of the laser beams LB1 and LB2 in the overlapping scanning area SA0 is increased or decreased by a quadratic function, the intensity around the ends of the overlapping scanning area SA0 is increased. The change in is smooth. Therefore, even when the partial scanning areas by the laser beams LB1 and LB2 are displaced in the scanning direction, the change in the total sum of the intensities of the laser beams LB1 and LB2 can be made small, and both ends of the overlapping scanning area SA0 can be reduced. The unevenness does not occur in the part that hits. Therefore, a higher quality graphic pattern can be drawn.

As a modification of the first embodiment, as shown in FIG. 9, the laser beam L in the overlap scanning area SA0 is used.
The increase and decrease in strength of B1 and LB2 may be linearly changed. In this case as well, the total sum of the intensities of the two laser beams LB1 and LB2 can be made substantially constant as in the first embodiment, but when compared with the first embodiment, as shown in FIG. Is different.

In the first embodiment, the modulation control unit 33 causes the same optical deflectors 14a and 14b to perform the modulation by the image signal and the light intensity correction. However, instead of this, the image signal is used. The modulation and the light intensity correction may be performed by separate modulators.

Next, a second embodiment of the present invention will be described. The graphic pattern drawing apparatus 101 of the second embodiment differs from the graphic pattern drawing apparatus 1 of the first embodiment in the following points. As shown in FIG. 10, a graphic pattern drawing device 101
Is an optical system that participates in the first laser beam LB1 and a second optical system
And the optical system related to the laser beam LB2 are disposed on separate mounting tables 7a and 7b. Moreover, the folding mirror 16 which is the only one in the first embodiment has the first laser beam LB.
1 is divided into a folding mirror 16a on the side involved in 1 and a folding mirror 16b on the side involved in the second laser beam LB2, and both folding mirrors 16a, 16b are provided.
Is not on a straight line and is displaced in the x direction in the figure.

Further, this graphic pattern drawing apparatus 101
The modulation control unit 33 in the control system of FIG.
The configuration is similar to that of the embodiment, and the raster data sent to the first optical modulator 11a is delayed. The other configurations are the same as those in the first embodiment.

The graphic pattern drawing apparatus 101 thus configured can draw a high quality graphic pattern without so-called seam deviation, while realizing a wide area to be scanned, as in the first embodiment. Further, the optical system related to the first laser beam LB1 and the second laser beam LB
Since the optical system related to 2 is configured as a separate part, the parts can be easily replaced.

Next, a third embodiment of the present invention will be described. The graphic pattern drawing apparatus 201 of the third embodiment has the same structure as that of the graphic pattern drawing apparatus 101 of the second embodiment, except that the second mounting table 7b and an optical system related to the second laser beam LB2 arranged therein are provided. Is excluded. That is, as shown in FIG. 11, the graphic pattern drawing apparatus 201 emits the laser beam LB1 emitted from the first laser light source 10a.
Optical modulator 11a and reflection mirror 1 arranged on the mounting table 7a
2a, the beam expander 13a, the optical deflector 14a, the scanning lens 15a, and the folding mirror 16 to irradiate the photosensitive material 3 so that the first laser beam LB1 alone is applied to the first and second partial scanning areas SA1. SA2 is being scanned.

More specifically, when one feed in the sub-scanning direction is completed and the scanning of the first partial scan area SA1 is completed, a mechanism (not shown) moves the mounting table 7a by a predetermined feed amount S in the main scanning direction. The optical system involved in the first laser beam LB1 arranged on the mounting table 7a is moved to the second partial scanning area SA2 side. The predetermined feed amount S is L−, where L is the length of the partial scanning areas SA1 and SA2 in the main scanning direction and W is the length of the overlapping scanning area SA0 in the main scanning direction.
W.

Further, this figure pattern drawing device 201
The modulation control unit 33 in the control system of FIG.
By removing the components on the side that controls the second optical modulator 11b from the embodiment, only the configuration on the side that controls the first optical modulator 11a is provided, as shown in FIG. 12, both the first partial image data D1 and the second partial image data D2 are sent from the front-end processor 31 to the buffer 40a, and the correction data memory 48a is shown in FIG. Both the first correction data indicating that the overlapping part increases from 0 to 1 and the second correction data indicating that the overlapping part decreases from 1 to 0 shown in FIG. 6 are stored at different addresses. . The modulation controller 41 uses the first and second partial scan areas SA.
The read start address in which the first correction data or the second correction data is stored is specified on the basis of the information indicating which of 1 and SA2 is drawn.

As in the first embodiment, the graphic pattern drawing apparatus 201 thus configured can draw a high-quality graphic pattern without so-called seam deviation while realizing a wide area to be scanned. Further, the plurality of partial scan areas SA1 and SA2 can be scanned only by the optical system related to the first laser beam LB1, and the configuration can be made compact.

Next, a fourth embodiment of the present invention will be described. The graphic pattern drawing apparatus 301 of the fourth embodiment has the same structure as that of the graphic pattern drawing apparatus 201 of the third embodiment.
0a, the optical modulator 11a and the reflection mirror 12a are excluded. That is, as shown in FIG. 13, the graphic pattern drawing device 301 emits the laser beam LB11 toward the beam expander 13a.
9 is arranged on the mounting table 7a.

The laser diode 309 is a semiconductor laser in which carriers are injected and excited by a junction and can directly perform modulation according to a control signal from the outside. In this embodiment, the laser diode 309 is stored in the auxiliary data memory. Direct modulation is performed based on the first correction data or the second correction data.

As in the first embodiment, the graphic pattern drawing apparatus 301 thus constructed can realize a wide area to be scanned and can draw a high-quality graphic pattern without so-called seam deviation. Further, by using the laser diode 309, it is possible to eliminate the need for an optical modulator and further simplify the configuration.

Next, a fifth embodiment of the present invention will be described. The graphic pattern drawing apparatus 401 of the fifth embodiment is obtained by adding a light amount correction filter to the configuration of the graphic pattern drawing apparatus 101 of the second embodiment. That is, as shown in FIG. 14, the graphic pattern drawing device 401 includes the first and second light amount correction filters 410a and 410 in the optical path from the first and second folding mirrors 16a and 16b to the photosensitive material 3.
This is a configuration in which each b is provided.

First and second light amount correction filters 410
Reference numerals a and 410b are intended to optically correct the intensity of the laser beam based on the first and second correction data shown in FIGS. 5 and 6 instead of electrically correcting it. The transmittances of the portions a1 and a2 corresponding to the overlapping scanning area of are changed with gradation.
Such a transmittance distribution is created by a method similar to that of the continuously variable ND filter.

As in the first embodiment, the graphic pattern drawing apparatus 401 thus constructed can draw a high-quality graphic pattern without so-called seam deviation while realizing a wide area to be scanned. Further, since the electric power correction of the laser beam is not necessary, the correction data memories 48a and 48b can be removed, and the configuration of the control system can be simplified.

Next, a sixth embodiment of the present invention will be described. The graphic pattern drawing apparatus 501 of the sixth embodiment applies the light amount correction filter used in the fourth embodiment to the configuration of the third embodiment in which one laser light source scans two partial scan areas SA1 and SA2. It is a thing. That is, as shown in FIG. 15, the graphic pattern drawing apparatus 501 includes only the optical system for the first laser beam LB1, and the folding mirror 16 is provided.
In this structure, a light amount correction filter 510 is arranged in the optical path from a to the photosensitive material 3.

The light quantity correction filter 510 has a portion 51 where the transmittance changes with gradation at both ends thereof.
1, 512, and when scanning the first partial scan area SA1, the portion 511 on the side of the second partial scan area SA1 is located on the overlapping scan area SA0, and the second partial scan area SA2 is When scanning, the portion 512 on the opposite side is located on the overlapping scanning area SA0. The graphic pattern drawing apparatus 301 thus configured can draw a high quality graphic pattern after simplifying the configuration of the control system, as in the fifth embodiment.

Although some embodiments of the present invention have been described in detail above, the present invention is not limited to these embodiments. For example, the Japanese Patent Publication No.
As disclosed in Japanese Patent No. 57566, one polygon mirror is irradiated with the first and second laser beams LB1 and LB2, or the surface to be scanned is divided into three or more partial scanning regions. Needless to say, the present invention can be implemented in various forms without departing from the scope of the invention.

[0050]

As described above in detail, according to the light beam scanning device of the present invention, even when the partial scanning areas are displaced in the scanning direction, the scanning lines are not broken or the connecting portions of the partial scanning areas are damaged. You can prevent duplication. For this reason, with the realization of a wide area to be scanned, if there is overlap or loss of images,
It is possible to obtain a high-quality image without so-called seam shift.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part of a graphic pattern drawing device 1 as a light beam scanning device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing partial scan areas SA1 and SA2 on a scan target area and their overlapping scan areas SA0.

FIG. 3 is a block diagram showing a configuration of an electric control system of the graphic pattern drawing device 1.

FIG. 4 is an explanatory diagram showing how the entire image data DP is divided into first partial image data D1 and second partial image data D2.

FIG. 5 is a graph showing the contents of first correction data.

FIG. 6 is a graph showing the contents of second correction data.

FIG. 7 is a graph showing the intensities of the first laser beam LB1 and the second laser beam LB2 in the vicinity of the overlapping scanning area SA0.

FIG. 8 shows a first laser beam LB1 and a second laser beam LB when the partial scanning area SA1 is deviated in the main scanning direction.
It is a graph which shows the change of the sum total of strength with 2.

FIG. 9 is a graph showing a change in the total sum of intensities of a first laser beam LB1 and a second laser beam LB2 in a modification of the first embodiment.

FIG. 10 is a perspective view showing a main part of a graphic pattern drawing device 101 according to a second embodiment of the present invention.

FIG. 11 is a perspective view showing a main part of a graphic pattern drawing device 201 according to a third embodiment of the present invention.

FIG. 12 is a block diagram showing a configuration of an electrical control system of a graphic pattern drawing device 201 according to a third embodiment.

FIG. 13 is a perspective view showing a main part of a graphic pattern drawing device 301 according to a fourth embodiment of the present invention.

FIG. 14 is a perspective view showing a main part of a graphic pattern drawing device 401 according to a fifth embodiment of the present invention.

FIG. 15 is a perspective view showing a main part of a graphic pattern drawing device 501 according to a sixth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Graphic pattern drawing apparatus 3 ... Photosensitive material 5 ... Table 7, 7a, 7b ... Mounting table 8 ... Optical system 10a, 10b ... Laser light source 11a, 11b ... 2nd light modulator 12a, 12b ... Reflection mirror 13a, 13b ... beam expanders 14a, 14b ... optical deflectors 15a, 15b ... scanning lenses 16, 16a, 16b ... folding mirrors 17a, 17b ... main scanning motor 21 ... sub-scanning motor 31 ... front-end processor 33 ... modulation control unit 35 ... scanning Control unit 40a, 40b ... Buffer 41 ... Modulation controller 42a, 42b ... RIP 43a, 43b ... Image memory 44a, 44b ... Adder 45a, 45b ... D / A converter 46a, 46b ... Modulator driver 47a, 47b ... Address Counters 48a, 48b ... Correction data memory 51 ... Scanning controller La 53, 54 ... Main scanning driver 55 ... Sub scanning driver 101 ... Graphic pattern drawing device 201 ... Graphic pattern drawing device 301 ... Graphic pattern drawing device 309 ... Laser diode 401 ... Graphic pattern drawing device 410a, 410b ... Second light amount correction Filter 501 ... Graphic pattern drawing device 510 ... Light amount correction filter D1 ... First partial image data D2 ... Second partial image data LB1 ... First laser beam LB2 ... Second laser beam SA1 ... First partial scanning area SA2 ... second partial scan area SA0 ... overlap scan area

Claims (1)

[Claims] 1. A partial scanning region obtained by dividing a surface to be scanned into a plurality of parts in a scanning direction by using a scanning means having a light beam emitting part for emitting a light beam and an optical deflector for deflecting the light beam. In the light beam scanning device for scanning in the above-mentioned manner, the deflection direction of the optical deflector is determined such that two adjacent ones of the plurality of partial scanning regions partially overlap in the scanning direction, and The energy of the light beam monotonically decreases at the overlapping portion of the partial scanning areas when scanning one partial scanning area, and the overlapping of the partial scanning areas when scanning the other partial scanning area of the two. The energy of the light beam from the light beam emitting portion is changed so that the energy of the light beam monotonously increases in the portion and the total energy of the light beam in the overlapping portion is substantially the same as the portion other than the overlapping portion. Light bee to adjust Light beam scanning apparatus characterized in that a regulating means.